Bug 21219 - mips gas 2.26 report error:opcode not supported on this processor: mips32r2 (mips32r2) `mttc0 $0,$25,1'
Summary: mips gas 2.26 report error:opcode not supported on this processor: mips32r2 (...
Alias: None
Product: binutils
Classification: Unclassified
Component: gas (show other bugs)
Version: 2.26
: P2 critical
Target Milestone: ---
Assignee: Not yet assigned to anyone
Depends on:
Reported: 2017-03-06 07:51 UTC by zycdywe
Modified: 2019-04-29 04:29 UTC (History)
3 users (show)

See Also:
Target: mips32r2 mips34kc
Last reconfirmed:

proposed fix (2.04 KB, patch)
2017-03-07 14:49 UTC, Matthew Fortune
Details | Diff

Note You need to log in before you can comment on or make changes to this bug.
Description zycdywe 2017-03-06 07:51:25 UTC
there is a bug in binutils2.26 of GAS, when it's ok in binutils2.20, and report an error in binutils2.26.

the case is assamble code embedded, mips32r2 and the core is mips 34kc. 
assamble code:do { __asm__ __volatile__( "%(mttc0\t %z0,$" "25" "," "1" "; ehb%)" : : "dJ" (0)); } while (0);

then gcc will compile the assamble code into " mttc0    $0,$25,1; "

when I use gas 2.26 to assamble the .s file , it report error below, but it's ok for gas 2.20
Error: opcode not supported on this processor: mips32r2 (mips32r2) `mttc0 $0,$25,1'

case below:

mttc0    $0,$25,1;
mftc0    $2,$25,0;

as2.20 -G 0 -G 0 -EB -mips32r2 -mno-dsp -O2 -g -no-mdebug -mabi=32 -march=34kc --trap -o 2.o 2.s   --  ok

as2.26 -G 0 -G 0 -EB -mips32r2 -mno-dsp -O2 -g -no-mdebug -mabi=32 -march=34kc --trap -o 2.o 2.s   --  error
2.s: Assembler messages:
2.s:3: Error: opcode not supported on this processor: mips32r2 (mips32r2) `mttc0 $0,$25,1'
2.s:4: Error: opcode not supported on this processor: mips32r2 (mips32r2) `mftc0 $2,$25,0'
Comment 1 Matthew Fortune 2017-03-07 14:49:31 UTC
Created attachment 9881 [details]
proposed fix

I have seen this before (and forgotten it without reporting a bug!). I believe the origin of this is actually with the new .module directive support that I added quite a long time ago. The default enabled ASEs for any given architecture are lost before they can be applied.

Proposed patch is attached.
Comment 2 Faraz Shahbazker 2019-04-29 04:29:12 UTC
The following commit on master resolves this:


commit 3315614d19a7fb409227298ead9b356bdbcca3bc
Author: Matthew Fortune <matthew.fortune@mips.com>
Date:   Tue Apr 9 10:34:48 2019 -0700

    [MIPS] Apply ASE information for the selected processor
    GAS does not enable implicit ASEs for most MIPS processors.
    The rework of option handling done as part of .module implementation
    left the implicit ASE logic broken and default enabled ASEs for
    most processors did not get applied.  This patch ensures the ASE
    information is carried forward to the point where it is required.
    	* config/tc-mips.c (mips_set_options) <init_ase>: New field.
    	(file_mips_opts, mips_opts) <init_ase>: Initialize new field.
    	(file_mips_check_options): Propagate initial ASE settings.
    	(mips_after_parse_args, parse_code_option): Track the initial
    	ASE settings for a CPU.
    	(s_mipsset): Restore the initial ASE settings when reverting
    	to the default arch.
    	* testsuite/gas/mips/elf_mach_p6600.d: New test.
    	* testsuite/gas/mips/mips.exp: Run the new test.